1. Field of the Invention
The present invention relates to a fuel system containing a shape memory alloy. More particularly, the present invention relates to a fuel system containing a part made from a shape memory alloy to control fuel as a function of temperature or an electrical device. The shape memory alloy will change shape at a defined temperature or in a particular temperature range thereby affecting a control feature internal to a component in the fuel system, and as a result, changing the fuel flow and/or pressure characteristic. The component may be a biasing spring.
2. Description of the Prior Art
Shape memory alloys have been used as the material for components of internal combustion engines. For example U.S. Pat. No. 5,603,302 to Minagawa et al discloses a fuel supply system for an internal combustion engine. The shape memory alloy is used to affect the sealing ability of a valve body with reference to temperature. A simple pressure relief valve is provided to reduce the effect of pressure waves transporting through the fuel system. The pressure relief valve does not function as the primary pressure control mechanism in the fuel system.
Another example is U.S. Pat. No. 4,790,343 to Mochizuki which pertains to a pressure regulator having a spring made from a shape memory alloy in the vacuum reference chamber.
U.S. Pat. No. 4,774,923 to Hayashi relates to the use of a shape memory alloy to create a two-stage pressure system. The spring made of shape memory alloy causes a regulator to regulate at a higher pressure at higher temperatures and lower pressure at lower temperatures by controlling the fuel floe through the outlet of the regulator. The regulator is a standard by-pass return type regulator.
Another system employing shape memory alloy is disclosed in U.S. Pat. No. 5,551,519 to Watson et al, in which a shape memory alloy is used to limit the actuation of an automatic choke system as a function of temperature. The air input into a fuel system is thereby controlled.
None of the foregoing references disclosed the use of a shape memory alloy component in a non-return type regulator, and none of the references discloses the use of a shape memory alloy component in a pressure regulator of a fuel system.